Iodine Hollow Cathode Development for Electric Propulsion

In electric propulsion for space applications, the exploration of alternative propellants has gained significant importance due to limited resource availability and economic considerations. This challenge has led researchers to investigate several possible candidates, with iodine emerging as a promising choice due to its favourable chemical and physical properties for propulsive performance, as well its lower cost and simpler storage conditions compared to xenon. However, iodine corrosive nature presents a disadvantage, as it reacts highly with many common materials used in the aerospace field, exposing materials to harsh conditions. The development of an iodine hollow cathode derives from the lack of positive results in long-term tests with this propellant. The designed cathode is capable of sustaining a discharge current in the range of 1-3 A to an external anode and it is equipped with LaB6 as emitter material. In order to study and investigate the interaction between iodine and components after testing, the cathode has been conceived fully dismountable. The activity is carried out by DICI-UniPi and DCCI-UniPi and comprises the development of an innovative iodine feeding system for iodine with reduced heating power consumption. After tests, the components undergo chemical analysis techniques, such as SEM-EDS to characterize cathode materials. The objective of this research is to demonstrate the effectiveness of using iodine as alternative propellant for hollow cathodes, particularly with LaB6 as insert, and to identify potential issues revealed during the tests, such as material selection and functional characterization of the cathode.